In this game you have an island with some buildings on it. You need to develop your island and protect it from the invaders. You can build and upgrade various buildings placing them on the ground or on top of other buildings. Some of the buildings have weapons. You can click on any of them while being attacked and shoot the weapons adjusting the power and the angle with the mouse. It'll take some time for the weapon to reload. You'll be switched to the next available weapon automatically to be able to continue shooting.